Noticeable from the caseback, the oscillating mass with the motion is delicately engraved. It's constructed from eighteen-karat gold and decorated by hand with a barley grain pattern, performed by guilloche Should your Omega has the phrases 'Learn Chronometer' on the dial—as is witnessed inside the Seamaster Diver 300M—you are able https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/